Horned Dorset is one of the three Dorset breeds of sheep all with bouncy Down-type fleece that resists felting. Dorset Down and Horned Dorset are originally from England. Dorset Poll was developed in the 20th century from this breed and is not endangered, in fact it is very common.
This is a photo by Sarah MacKay-Smith of one of her ewes at Cullenstone Farm, where we bought this fleece in the Northern Shenandoah Valley. They grow some of the ”nicest Dorset fleece” around!